fix the bug in complex constructor

Complex constructor should call __complex__ before call __float__.
And should not call PyNumber_Float in that special method.
Also add error checking after calling PyNumber_Float.

src/runtime/complex.cpp

@@ -712,22 +712,6 @@ template <ExceptionStyle S> static Box* try_special_method(Box* self) noexcept(S
         return None;
     }
 
-    static BoxedString* float_str = internStringImmortal("__float__");
-    if (PyObject_HasAttr((PyObject*)self, float_str)) {
-        Box* r_f = callattrInternal<S, NOT_REWRITABLE>(self, float_str, CLASS_ONLY, NULL, ArgPassSpec(0), NULL, NULL,
-                                                       NULL, NULL, NULL);
-        if (!PyFloat_Check(r_f)) {
-            if (S == CAPI) {
-                if (!PyErr_Occurred())
-                    PyErr_Format(PyExc_TypeError, "__float__ returned non-float (type %.200s)", r_f->cls->tp_name);
-                return NULL;
-            } else {
-                raiseExcHelper(TypeError, "__float__ returned non-float (type %.200s)", r_f->cls->tp_name);
-            }
-        }
-        return (BoxedFloat*)r_f;
-    }
-
     static BoxedString* complex_str = internStringImmortal("__complex__");
     if (PyObject_HasAttr((PyObject*)self, complex_str)) {
         Box* r = callattrInternal<S, NOT_REWRITABLE>(self, complex_str, CLASS_OR_INST, NULL, ArgPassSpec(0), NULL, NULL,
@@ -754,6 +738,7 @@ template <ExceptionStyle S> static Box* try_special_method(Box* self) noexcept(S
 
         return static_cast<BoxedComplex*>(r);
     }
+
     return None;
 }
 
@@ -777,16 +762,11 @@ template <ExceptionStyle S> Box* _complexNew(Box* real, Box* imag) noexcept(S ==
     }
 
     Box* _real = try_special_method<S>(real);
-    Box* _imag = try_special_method<S>(imag);
 
     if (_real != None && _real != NULL) {
         real = _real;
     }
 
-    if (_imag != None && _imag != NULL) {
-        imag = _imag;
-    }
-
     double real_f, imag_f;
     bool real_is_complex = false, imag_is_complex = false;
     if (real == None || real == NULL) {
@@ -795,7 +775,10 @@ template <ExceptionStyle S> Box* _complexNew(Box* real, Box* imag) noexcept(S ==
         real_f = ((BoxedComplex*)real)->real;
         real_is_complex = true;
     } else {
-        real_f = ((BoxedFloat*)PyNumber_Float(real))->d;
+        Box* res = PyNumber_Float(real);
+        if (!res)
+            throwCAPIException();
+        real_f = ((BoxedFloat*)res)->d;
     }
     if (imag == None || imag == NULL) {
         imag_f = 0.0;
@@ -803,7 +786,10 @@ template <ExceptionStyle S> Box* _complexNew(Box* real, Box* imag) noexcept(S ==
         imag_f = ((BoxedComplex*)imag)->real;
         imag_is_complex = true;
     } else {
-        imag_f = ((BoxedFloat*)PyNumber_Float(imag))->d;
+        Box* res = PyNumber_Float(imag);
+        if (!res)
+            throwCAPIException();
+        imag_f = ((BoxedFloat*)res)->d;
     }
 
     if (imag_is_complex) {
@@ -817,6 +803,7 @@ template <ExceptionStyle S> Box* _complexNew(Box* real, Box* imag) noexcept(S ==
     return new BoxedComplex(real_f, imag_f);
 }
 
+
 template <ExceptionStyle S> Box* complexNew(BoxedClass* _cls, Box* _real, Box* _imag) noexcept(S == CAPI) {
     if (!isSubclass(_cls->cls, type_cls)) {
         if (S == CAPI) {